Should I open up the stock intake to accept my 70mm t body?

yes open it and no dremel its like digind to china with a spoon.if you dont have the air tools the buy the stones from sear or were ever and use a multi speed drill one that plugs in youll be there a while
 
I opened my stock intake with a dremel and a grinding stone...opened it to 65mm to match my TB....took about 25 minutes...just make sure you stuff a rag in the intake to keep all the "scraps" from falling in. (I tappered mine).
 
oh it will i just assume that it would take forever because i never seen a big stone for my dremel there all little but if you can find the right size stone than more power to ya
 
Open it up - however, don't expect much to change when you install it. The stock lower intake is a bigger bottleneck to increased flow than the stock throttle body is. So even though more air can move through the throttle body - it won't, cause it can't get past the lower intake. Tmoss can port the lower for you - that'll make a difference you can feel.